They date back hundreds of thousands of years and are consistently the most stable words. Some of them even have projected lifespans up to 100,000 years, according to a new study by Prof Mark Pagel which was published in the Philosophical Transactions of the Royal Society journal on Jan 1.

Pagel has been studying the history of Indo-European languages, which form the basis of how we speak today, alongside evolutionary language scientists from Santa Fe Institute.

He says the long lives of these words can be found in the Bantu languages of Africa and the Austronesian languages of the South Pacific as well.

“It is remarkable to think that words used today, in particular ‘two’, ‘three’, and ‘five’ connect us with ancestors from perhaps 10,000 or more years ago who would have used words similar to those in use today.”

What is particularly surprising is how these words have lived so long – spanning nearly the entire history of the Indo-European language family – and have done so without a writing system, being passed on solely in the spoken tradition,” Pagel said.

But what makes these words persist? Pagel and his team think it could be due to our ancient brain regions’ ability to perceive small numbers of objects without counting.

The researchers point to evidence that even animals can perceive numbers despite their lack of any formal counting system like that of humans.

Pagel explained: “Given that we know that these low limit number words are some of the first words that children learn, it might tell us that simple counting abilities have played an important role in our daily lives, and in our communication, throughout our evolution.”